A widely used type of such a network is defined in IEEE standards 802.11. In a network of this type, stations support a plurality of transmission channels, one of which must be selected for communication between the stations when the network is starting up. The available transmission quality can differ from one channel to the other, for various reasons. For example, a channel may be occupied already by stations of another network, it may carry noise from non-network sources, signal attenuation may be high due to destructive interference of multiple propagation paths, etc. Conventionally, a station determines a suitable channel for network communication based on a scan in which energy levels of all supported channels are detected. A channel may then be found suitable for network communication if the level of noise from other sources on that channel is below a pre-determined threshold or if it is lower than that of the other channels.
Such an approach may be fast and simple to implement, but is not always satisfying, since a sufficiently noise-free channel is not always available, and the least noisy one of the channels is not always the one that provides best communication quality. In order to allow a choice between a plurality of more or less noisy channels, it has been suggested to detect certain spectral characteristics of the noise in the channels, and to decide, based on said characteristics, whether or to what degree the noise is likely to be detrimental to network communication. Implementation of such methods tends to be expensive, since detection of the spectral characteristics requires specific circuitry which increases the costs of the stations that carry out such methods. Further, there seems to be no spectral characteristic or set of characteristics available by which it could be judged reliably whether or to what extent a certain profile of noise that is present on a channel is detrimental to network communication.
It is therefore desirable to provide a method for assessing quality of a transmission channel in a wireless network which is easy to implement and requires, if at all, only a minimum of dedicated hardware.